Gas discharge lamp with a movable baffle adjacent one electrode



. Dec. 2. 1969 H. GREBER 3,482,141

GAS DISCHARGE LAMP WITH A MOVABLE BAFFLE ADJACENT ONE ELECTRODE Filed Dec. '7, 1967 INVENTOR. if? 9,649

United States Patent 3,482,141 GAS DISCHARGE LAMP WITH A MOVABLE BAFFLE ADJACENT ONE ELECTRODE Henry Greber, 225 W. 80th St, Apt. 8-D, New York, N.Y. 10024 Filed Dec. 7, 1967, Ser. No. 688,871 Int. Cl. H01j 7/44 US. Cl. 315-49 4 Claims ABSTRACT OF THE DISCLOSURE Agas discharge lamp has within the envelope a controllable battle which limits the current flow. The baffle is located adjacent one electrode and the passage between the electrodes is adjusted either automatically by means of bimetallic strips or from the outside by means of an electromagnet. This arrangement replaced the usual ballast.

This invention is related to a gas discharge lamp which can function without a ballast, and whose light output can be controlled, particularly for dimming purposes. Its operation is based on a valve means in its tube which increases or decreases the passage area of the current through the tube, if the magnitude of the current is smaller or larger than its preset value. The movement of the valve means in direction of closing or opening of the passageway through the tube is accomplished by a thermostat in the tube, or a solenoid outside the tube. Both means function automatically, but can be set manually for dimming the lamp.

The great disadvantage of gas discharge lamps, including the commonly used fluorescent lamps, is that they cannot operate without ballasts. Without these, the currents in gas discharge lamps would reach runaway proportions and destroy them. Ballasts, however, make not only the installation, but also the operation of gas discharge lamps expensive, since ballasts cause a loss of energy, which on the average, amounts to about ten percent of the rated of the lamp. In addition to losses of energy, ballasts cause voltage drops, lowering of the power factor of lighting installations and noise. The importance of this problem to the national economy is apparent. Gas discharge lamps, and specifically fluorescent lamps are now used by the millions. The deletion of their ballasts would amount to substantial savings, not only in their purchase and installation costs, but also in the cost of electric energy lost in them. The order of magnitude of this saving can be estimated to be hundreds of millions of dollars. Up to now, inventive efforts have been principally directed towards minimizing the numerous disadvantages of the ballast.

The primary purpose of this invention is to do away with the ballast altogether, by providing a way to operate a gas discharge lamp without it, and thereby to avoid all its disadvantages. Another purpose of this invention is to use the same method and means to control the light output of a gas discharge lamp, particularly for dimming. Still another purpose of this invention is to provide a complete interchangeability of incandescent and fluorescent lamps, which is very much desired by the public. A still further objective of this invention is to use the same method and means to control the emission of the thermionic current of the gas discharge lamp, particularly in thyratrons, and especially for interruption of such current. Thereby, a thyratron provided with means according to this invention can serve as an effective substitute for a breaker.

.The concept on which this specification is based consists in providing a valve means in the gas discharge tube 3,482,141 Patented Dec. 2, 1969 ICE which decreases the passageway through it when its current surpasses a preset value. If the current is smaller than this value, the valve means increase the area of the passageway of the current through the lamp. The valve operates automatically, but can be manually adjusted for dimming. Thevalve can be controlled thermally, electromagnetically and mechanically. The way in which this concept is incorporated into different design solutions can be seen from this specification and from the accompanying drawing.

In this drawing, FIGURE 1 shows an elevational view of a fluorescent lamp provided with a valve according to this invention and with means for adjusting its light output. In FIGURE 2 is shown an elevational view of one terminal of a broken away fluorescent lamp provided with a different thermostatically controlled valve. FIG- URE 3 presents also an elevational view one terminal of a fluorescent lamp provided with a different type of a thermostatically controlled valve. Another elevational view of one terminal of a fluorescent lamp with automatically controlled thermostatic valve, and with dimming by means of a solenoid is drawn in FIGURE 4. In FIGURE 5 can be seen a front view, and in FIGURE 6 side view of one terminal of a fluorescent tube flattened in one spot, at which it is provided with an electromagnet juxtaposed to a piece of soft iron.

In detailed consideration of these figures, it can be seen that tube 1 of a fluorescent lamp contains stem 2, provided with the usual filament, having two fins 4, and 5, which act as anodes in large wattage lamps. Stem 2 also carries a melted into it bimetallic strip 6, to which disc 7 is fastened. The same disc is shown in almost open position 7 with dashed lines. Bimetallic strip 6 is wrapped with the insulated heater wire 8, whose terminals are brought out to pins 9, 10 fastened in ferrule 11. The terminals of filament 3 are brought out to pins 12, 13. The terminals of the heater 8 are bypassed with adjustable rheostat, mounted in enclosure 15. Conductor 16 connects pin 9 with one terminal of the source of AC current 17, whose other terminal is connected, by means of wire 18, to pin 19 fastened in ferrule 20. The other pin 21 of ferrule 20 is connected, by means of conductor 22, to starter switch 23, which contains the contacts 24 and 25, as well as capacitor 26. The other terminal of starter switch 23 is connected, by means of conductors 27, to pin 13. The upper end of tube 1, a part of which is broken away at point 28, contains stem 29, carrying filament 30, provided with the metallic fins 31 and 32. Disc 7 can be made of a metallic sheet, or of glass.

The part of a fluorescent tube 33 shown in the elevational view of FIGURE 2, contains stem 34, supporting filament 35. One end of filament 35 is carried out, by means of conductor 36, to pin 37, that is connected through the pointed conductor 38, to a source of AC voltage, which is not shown. The other end of filament 35 is connected to a strip of metal which carries valve disc 40. The same disc 40 is also fastened to another metallic strip 41, which is made of a metal of a different thermal expansion coeflicient than that of the metal of which strip 39 is made. The two strips 39 and 41 form together ,a bimetallic element, which in addition also serves as heating element, since the current from the AC source (not shown), flows through conductor 42 (marked with an arrow), into pin 43, fastened in ferrule 44, through metallic strip 41 and through metallic disc 40, and metallic strip 39 into the filament 35.

The part of the gas discharge tube 45, shown in elevation in FIGURE 3, contains stem 46, carrying filament 47. Valve disc 48, is supported on three metallic helixes 49, 50, and 51, which expand because of the heat radiated from filament 47, and decrease the passage through the opening 52 of annular ring 53, which is supported on wires 54, and 55. Ferrule 56 is equipped with pins 57 and 58.

In FIGURE 4 can be seen a part of the fluorescent tube 59 containing stem 60 supporting filament 61. Stem 60 also supports the bimetallic strip 62, to whose end is fastened disc valve 63. The bimetallic strip 62 is wrapped with the insulated heater wire 64. One end of heater element 64 is connected, by means of conductor 65, to pin 66, which in turn is connected by means of conductor 67 to a source of AC (not shown). The other end of heater element 64 is connected to filament 61. The opposite terminal of filament 61 is connected, by means of conductors 68 to ferrule 69, which is linked, by means of conductor 70, to a starter switch (not shown). Ferrules 66 and 69 are fastened in ferrule 71. The solenoid coil 85 is connected in series with adjustable rheostat 86. Conductors 86 and 87 connect solenoid 85 and rheostat 86 in parallel to the terminals 66 and 69.

Since FIGURES and 6 show different view of the same object, any of its parts is designated in both views with the same numeral. Tube 72 can be seen in the front elevation in FIGURE 5, and in the side elevation of FIGURE 6, is flattened at point 73, so that the two essentially flat walls of the tube are close to each other. The end part of tube 74, however, is of a circular cross section and carries ferrule 75, provided with pins 76 and 77. At point 73 is mounted electromagnet core 78, provided with windings 79. Conductors 80 and 81 are connected in series with the filament 82 mounted on stem 83. If control of the light output is desired, it can be achieved by an adjustable rheostat connected in parallel or in series with windings 79. Juxtaposed to electromagnet core 78 is a piece of soft iron 84, cemented to the wall of the tube.

The mode of operation of this invention closely resembles that of a thermostat controlling the temperature of an electrically heated room. When the current through the gas discharge lamp is greater than its preset value, the flap of the valve decreases the passageway through the tube, so that the current in it is decreased. In the opposite case, when the current through the gas discharge lamp is smaller than the preset, the flap of the valve opens the passageway through the tube, and the current through it is increased. This automatic control is sufficient in the majority of gas discharge lamp applications. In some cases, however, dimming of these lamps is desired. In such cases the flap of the valve can be moved manually. This can be done by thermal, electromagnetic or mechanical means. The thermal means consist of a heater wound on the thermostat. If a current, whose magnitude can be controlled with a thermostat, flows through the heater element, the flap of the valve is somewhat turned in direction of closing, or opening, as desired, and

fluctuates by the previously described automatic control mechanism around the preset position. If electromagnetic control is applied, the flap of the valve is of iron, which is moved by action of the magnetic field on it. The magnetic field is produced by a solenoid coil mounted on the tube near its terminal, and passed by the same current that flows through the lamp. If mechanical means for adjustment of the valve for dimming are used, part of the walls of the tube itself serve as a part of the valve. The tube can be flattened and the two opposite flat walls can be brought in close proximity by pushing them toward each other. This can be brought about by simple lever mechanisms (which are not shown), or by electromagnetic means shown in FIGURES 5 and 6. In FIG- URE l is shown the application of this invention in conjunction with a starter switch. In this case the ends of the filaments are brought out. The starter switch serves to close the circuit through the filaments in order to heat them. After a predetermined time, the starter switch is automatically opened, and the filaments are heated by ionic bombardment. The mode of operation of this invention remains the same when the more generally used at present instant start lamps are applied. The lamp according to this invention is so laid out that it starts at operating volage with its valve in open position, which immediately begins to close until it comes into its position corresponding to the steady state operation of the lamp.

In addition to gas discharge lamps including the flucrescent this invention can also be used for neon sign lamps and for mercury rectifiers, as well as for electronic lamps, particularly for thyratrons. Thyratrons provided with means according to this invention can be used as substitutes for DC and AC breakers. The invention itself can be modified, varied and changed by omission and substitution of components and by their adaptation to given conditions. All such changes, however, are within the scope and in the sense of the following claims defining the invention.

What is claimed is:

1. A ballastless, dimmable gas discharge lamp having inbuilt valve means operated with control means, which decrease the passage area through the tube when the current flowing through it surpasses a predetermined value, and increases the passage area through the tube when if the current flowing through the lamp is smaller than the mentioned preset value, said discharge tube has also additional control means, manually adjustable, which adjust said automatic control means so as to change the value of said preset current.

2. A ballastless, dimmable gas discharge lamp as in claim 1, with said automatic control means consisting of a bimetallic strip, and said manual means consisting of an insulated heater wire wound on said bimetallic strip, with the current in said heater wire being controlled by a manually adjustable rheostat.

3. A ballastless, dimmable gas discharge lamp, as in claim 1, with said valve means having a flap of iron exposed to a magnetic field produced by a coil mounted on the tube of said gas discharge lamp, said coil being passed by the same current that flows through the gas discharge lamp.

4. A ballastless, gas discharge lamp as in claim 1, with said means of automatic control consisting of a part of tube of said gas discharge lamp being flattened, so that the two flat walls can be brought in close proximity by pushing them toward each other mechanically.

References Cited UNITED STATES PATENTS 1,930,132 10/1933 Reger 313220 X 2,906,905 9/1959 Wares 313-186 X 2,908,841 10/1959 Gerber 313-204 3,295,003 12/1966 Chernin 313-204 X JAMES W. LAWRENCE, Primary Examiner C. R. CAMPBELL, Assistant Examiner US. Cl. X.R. 

